1. Field of Invention
The present invention relates to an apparatus for adjusting temperature of oil for a vehicle and a method for controlling the apparatus, and more particularly to a technology which controls temperature of oil by using heat of exhaust gas from an engine.
2. Description of Related Art
When starting a vehicle, oil for an engine or transmission at low temperatures undergoes a warm-up process so that the oil can be maintained at an appropriate temperature for driving of the vehicle. After the oil is warmed up, the engine or transmission can operate normally.
A conventional oil warming-up method usually includes a first warm-up through which coolant is primarily warmed up by passing through a water jacket disposed in a combustion chamber of an engine and a second warm-up through which oil is then warmed up by performing heat exchange with the coolant. This method has a drawback in that warm-up is too slow. Accordingly, rapid warm-up which uses exhaust gas of a high temperature for warm-up has been recently, broadly used.
In case of a heat exchanger using heat of exhaust gas, exhaust gas and oil have to be appropriately controlled at each stage, i.e., before warm-up, during warm-up, and after warm-up. Since exhaust gas with a relatively high temperature and oil of a relatively low temperature exchange heat with each other, inappropriate heat exchange causes durability problems such as fouling and carbonization and affects ingredients of the exhaust gas, such as HC (hydrocarbon), CO, and NOx.
The information disclosed in this Background section is only for enhancement of understanding of the general background of the invention and should not be taken as an acknowledgement or any form of suggestion that this information forms the prior art already known to a person skilled in the art.